ClinicalClinical AnatomyAnatomy ofof thethe BreastBreast Dr. Roger A. Dashner Clinical Anatomist & CEO Advanced Anatomical Services Adjunct Associate Professor OU College of Health Sciences & Professions IntroductionIntroduction toto thethe BreastBreast

• (mammary glands) = modified sweat glands

• Lie in supf. fascia ant. to deep fascia of pec. major

• Btwn. glands & deep fascia is retromammary space

• (i.e., loose CT plane allowing free movement)

• Thus, glands NOT firmly attached to deep fascia Suspensory (Cooper’s) Ligaments

•Glands ARE firmly attached to skin via CT

• Fibrous septa anchor deep layer of skin to deep fascia

• These CT septa are called suspensory ligs. Pec.Pec. FasciaFascia && Susp.Susp. Ligs.Ligs. Structure of the

• Compartmentalized fat bounded by CT septa

• Glandular lobules drained by 15-20 lactiferous ducts

• Lactiferous ducts converge & open onto

• surrounds nipple & conceals sebaceous glands

• (i.e., produce lubrication for nipple) CompartmentalizationCompartmentalization GlandGland LobulesLobules && Lac.Lac. DuctsDucts FourFour QuadrantsQuadrants ofof thethe BreastBreast

• Upper outer (superolateral) quadrant

• Upper inner (superomedial) quadrant

• Lower outer (inferolateral) quadrant

• Lower inner (inferomedial) quadrant 44 QuadrantsQuadrants ofof thethe BreastBreast ClinicalClinical NotesNotes onon BreastBreast CancerCancer

• Majority of cancers develop in upper outer quadrant

• Large amount of glandular tissue here

•An axillary tail of breast tissue often extends into axilla AxillaryAxillary TailTail ofof thethe BreastBreast EarlyEarly BreastBreast CarcinomaCarcinoma AdvancedAdvanced BreastBreast CancerCancer

• Tumors may grow thru retromammary space

• Subsequently invade deep fascia & pec. major m.

• Leads to fixation of malignant breast lesion to chest wall

• Shortens suspensory (Cooper’s) ligs.

• Leads to irregular dimpling of skin or retraction of nipple AdvancedAdvanced CarcinomaCarcinoma FourFour BoundariesBoundaries forfor aa MastectomyMastectomy

• Clavicle – superior boundary

• (above rectus sheath) – inferior boundary

• Sternum (midline) – medial boundary

• Latissimus dorsi (ant. border) – lateral boundary MastectomyMastectomy BoundariesBoundaries TheThe AxillaAxilla ContentsContents ofof thethe AxillaAxilla

• Axillary sheath (axillary a. & brachial plexus)

• Axillary v. & lymphatics (outside sheath)

• Fat & connective tissue

• Cutaneous nerves ContentsContents ofof thethe AxillaAxilla TheThe AxillaryAxillary ArteryArtery

•Arises from subclavian a. at lat. border of 1st rib

• Becomes brachial a. at infr. border of teres major

• Surrounded by cords & brs. of brachial plexus

• Can be divided into 3 parts relative to pec. minor AxillaryAxillary ArteryArtery (Exposed)(Exposed) AxillaryAxillary ArteryArtery (Concealed)(Concealed) 33 PartsParts ofof thethe AxillaryAxillary ArteryArtery

• Part 1 –btwn. 1st rib & pec. minor

• (i.e., gives off supr. thoracic a.)

• Part 2 – deep to pec. minor

• (i.e., gives off thoracoacromial & lat. thoracic aa.)

• Part 3 – btwn. pec. minor & teres major

• (i.e., gives off subscapular, ant. & post. circ. humeral aa.) 33 PartsParts ofof thethe AxillaryAxillary A.A. VesselsVessels ofof thethe BreastBreast

• Enter from supr./med. & supr./lat. aspects

• Penetrate deep surface of breast

• Exhibit extensive brs. & anastomoses AnastomosesAnastomoses ofof thethe BreastBreast ArterialArterial SupplySupply ofof thethe BreastBreast

• Lateral (mammary) thoracic a.

• Internal (mammary) thoracic a.

• Intercostal aa.

• Thoracoacromial a. LateralLateral (Mammary)(Mammary) ThoracicThoracic ArteryArtery

• Branch of axillary a. (under pec. minor)

• Located along lat. aspect of thorax

• Supplies lat. thorax & lat.

• Specific blood supply from lat. mammary brs.

• Runs with lat. thoracic v. & long thoracic n.

• Vein is a tributary to axillary v. InternalInternal (Mammary)(Mammary) ThoracicThoracic ArteryArtery

• Branch of subclavian a.

• Located inside thorax just lat. to sternum

• Descends vertically across intercostal spaces

• Supplies ant. thorax & med. mammary gland

• Specific blood supply from med. mammary brs.

• Runs with int. thoracic v.

• Vein is a tributary to brachiocephalic v. LateralLateral && InternalInternal ThoracicThoracic Aa.Aa. LateralLateral && InternalInternal ThoracicThoracic Vv.Vv. IntercostalIntercostal ArteriesArteries

•Brs. of aorta or int. (mammary) thoracic aa.

• Located in intercostal spaces (btwn. ribs)

• Supply ant., post. & lat. thorax & breast

• Specific blood supply is from lat. mammary brs.

• (i.e., lat. cutaneous brs. of post. intercostal aa.)

• Run with intercostal vv. & nn.

• Veins are tributaries to azygos v. or int. thoracic v. LateralLateral MammaryMammary Brs.Brs. IntercostalIntercostal ArteriesArteries IntercostalIntercostal VeinsVeins ThoracoacromialThoracoacromial ArteryArtery

• Branch of axillary a. (under pec. minor)

• Located in ant. shoulder region

• Sends off 4 subsequent brs.

• Not generally major source of blood supply to breast FourFour BranchesBranches ofof thethe ThoracoacromialThoracoacromial ArteryArtery

• Pectoral br. – supplies pectoral region & upper breast

• Clavicular br. – supplies clavicle region

• Acromial br. – supplies upper shoulder region

• Deltoid br. – supplies lower shoulder region

• All accompanying vv. are tributaries to axillary v. ThoracoacromialThoracoacromial ArteryArtery AdditionalAdditional VenousVenous DrainageDrainage ofof thethe BreastBreast

• Cephalic v. CephalicCephalic VeinVein

• Tributary to axillary v.

•Only major supf. v. in vicinity of breast

• Primarily drains UL into deltopectoral triangle

• Some supf. venous drainage of breast CephalicCephalic VeinVein NervesNerves ofof thethe BreastBreast

• Cutaneous innervation

• Medial pectoral n.

• Lateral pectoral n.

• Long thoracic n. CutaneousCutaneous InnervationInnervation

• Via general sensory brs. of T1-T6

• (i.e., lat. & ant. cutaneous brs. of intercostal nn.)

• Note: T2 is of specific clinical significance CutaneousCutaneous InnervationInnervation IntercostobrachialIntercostobrachial NerveNerve

• Lat. cutaneous branch of T2

• Emerges from 2nd intercostal space

• Supplies skin on med. & post. arm

• Assoc. with referred pain from angina or heart attacks

• Heart symp. nn. carry afferents back to upper thoracic cord

• Visceral heart pain referred to somatic thoracic nn. IntercostobrachialIntercostobrachial NerveNerve MedialMedial PectoralPectoral NerveNerve

• Branch of med. cord of brachial plexus

• Derived from ventral rami of C8-T1

• Pierces pec. minor to enter pec. major

• Supplies pec. minor & part of pec. major LateralLateral PectoralPectoral NerveNerve

• Branch of lat. cord of brachial plexus

• Derived from ventral rami of C5-C7

• Runs above pec. minor to enter pec. major

• Supplies remainder of pec. major Med.Med. && Lat.Lat. PectoralPectoral Nn.Nn. LongLong ThoracicThoracic NerveNerve

• Derived from ventral rami of C5-C7

• Supplies serratus anterior superficially

• (i.e., holds UL to thoracic wall)

• Damage to this n. can occur during mastectomy

• Results in “winged scapula” LongLong ThoracicThoracic NerveNerve ““WingedWinged ScapulaScapula”” LymphaticsLymphatics ofof thethe BreastBreast

• Drain lymph from breast to series of nodes

• Lat. drainage is via 5 groups of axillary nodes

• Supr. drainage is via 1 group of interpectoral nodes

• Med. drainage is via 1 group of parasternal nodes

• Ultimate drainage is via subclavian lymph trunk to vv.

• (i.e., jxn. of subclavian v. & IJV) LymphaticLymphatic DrainageDrainage LymphLymph NodesNodes ofof thethe BreastBreast

• Pectoral (anterior) nodes

• Subscapular (posterior) nodes

• Humeral (lateral) nodes

• Central nodes

• Apical nodes

• Interpectoral (Rotter’s) nodes

• Parasternal nodes LymphLymph NodesNodes ofof thethe BreastBreast VascularVascular AssociationsAssociations ofof thethe BreastBreast LymphLymph NodesNodes

• Pectoral – assoc. with lat. thoracic vessels

• Subscapular – assoc. with subscapular vessels

• Humeral – assoc. with distal (3rd) part of axillary v.

• Central – assoc. with middle (2nd) part of axillary v.

• Apical – assoc. with proximal (1st) part of axillary v.

• Interpectoral – assoc. with pectoral vessels

• Parasternal – assoc. with int. thoracic vessels VascularVascular AssociationsAssociations ClinicalClinical NotesNotes onon AxillaryAxillary LymphLymph NodeNode DissectionsDissections

• 3 Levels of surgical dissections relative to pec. minor

• (i.e., opposite arrangement of 3 parts of axillary vessels)

• Level I – below (lateral to) pec. minor

• Level II – deep to pec. minor

• Level III – above (medial to) pec. minor PectoralisPectoralis MinorMinor DissectionsDissections ClinicalClinical SignificanceSignificance ofof BreastBreast LymphaticsLymphatics

• Cancer cells tend to spread along lymph passages

• Typical spread is supr./laterally to axillary lymph nodes

• More than 75% of drainage via axillary lymph nodes

• Most remaining drainage is medially to parasternal nodes

• Unilateral lymphatic blockage may occur

• Lymph (with cancer cells) can then drain to opposite side DrainageDrainage toto OppositeOpposite SideSide TheThe EndEnd ReferencesReferences

• Agur, A.M.R. & A.F. Dalley. Grant’s Atlas of Anatomy, 12th Ed., Lippincott Williams & Wilkins, Baltimore, MD, 2009. • Clemente, C. Anatomy: A Regional Atlas of the Human Body, 5th Ed., Lippincott Williams & Wilkins, Baltimore, MD, 2006. • Moore, K.L., A.F. Dalley & A.M.R. Agur. Clinically Oriented Anatomy, 6th Ed., Lippincott Williams & Wilkins, Baltimore, MD, 2010. • Netter, F.H. The CIBA Collection of Medical Illustrations, Volume 2: Reproductive System. CIBA-Geigy, Summit, NJ, 1986. •Netter F.H. Atlas of Human Anatomy, 4th Ed., Saunders Elsevier, Philadelphia, PA, 2006. • Tank, P.W. Grant’s Dissector, 14th Ed., Lippincott Williams & Wilkins, Baltimore, MD, 2009.